'Jones' hits funny bone

An infectious comedy, "Osmosis Jones" gets under your skin with laughs that are fast, slick and slippery and visuals as vivid as anything this side of Demerol.

In addition to producing this half-live-action/half-animated film, gross-out kings the Farrelly Bros. ("There's Something About Mary") direct Bill Murray in live-action sequences as Frank, a widowed father and zookeeper of questionable hygiene. Frank's unsanitary nature catches up to him when he eats a hard-cooked egg dropped on the ground by a monkey and ingests a particularly nasty supervirus, Thrax. Inside Frank's body -- an animated universe full of organ cities and artery superhighways -- Thrax (voiced by Laurence Fishburne) parades as the common cold, evading the body's defenses, and works on his lethal plan.

However, demoted white blood cell Osmosis Jones (voiced by Chris Rock), an inner-city immunization cop, is onto his plan and enlists cherry-flavored cold tablet Drix (voiced by "Frasier's" David Hyde Pierce) to help save Frank. No one believes them, of course, least of all politically shaky Mayor Phlegmming (voiced by William Shatner), who is more concerned with providing jobs by constructing a third chin. "A fat Frank is a happy Frank," says Phlegmming, who later threatens to flush Jones out in the next nosebleed if he causes trouble. Leah, the mayor's assistant (voiced by pop star Brandy Norwood), is Jones' sexy single-celled love interest, doing her best to keep Frank healthy and Jones out of harm's way.

With animation sequences directed by Piet Kroon and Tom Sito, Frank's body stands (and sits and lies down) as a richly textured biological world of wonder. Traditional, computer and CGI animation blend together in creating Frank's fully imagined innards. Exotic locations such as the Liver, the Brain and the Nose provide the setting for a cast of contagious characters. There's upstart politician Tom Colonic ("A Regular Guy," tout his campaign commercials), the grimy underworld germ Mafia, and an acne-based band (voiced by Detroit rapper Kid Rock and the late Joe C.).

Built-in bodily fluid humor fuels most jokes, and the Farrellys seem right at home capitalizing on some stomach-turning zit humor while still managing to pull off a little tenderness between Frank and his concerned daughter Shane (Elena Franklin). Although the live-action set pieces -- sometimes utilitarian and cinematically thin -- are little more than a framing device for the animated story, Murray remains fun to watch in his feverish stupor, prodded on by Farrelly-film vet Chris Elliott in a white-trash wig.

Like early Zucker brother films ("Airplane," "Naked Gun"), "Osmosis Jones" crams in so many jokes that your blood pressure will rise trying to keep track of them all. Writer Marc Hyman's script will leave you in stitches and send you back to science class with its many medical inside jokes. Puns fly by, while visual jokes flash in the background. A statue of a sperm cell in the Cerebellum Hall is inscribed with the words "Our Founder," and later, movie posters in Frank's theater of the subconscious read "Girls From the Bus Stop" and "I Forgot My Pants."

Chris Rock is dead-on as the white-celled wonder Jones who grew up "on the wrong side of the digestive tract" and is only slightly outdone by Fishburne's seething virus Thrax. As a cold tablet with his top on too tight, Pierce is perfectly cast against Rock's loud, unpredictable Jones, and Shatner is scarily believable as the know-it-all brain cell mayor.

For fans of animation and larger-than-life jokes, "Osmosis Jones" is just what the doctor ordered.